Microorganisms And Biotechnology Flashcards
What is the definition of biotechnology?
-applying biological organisms or enzymes to the synthesis, breakdown, or transformation of materials in the service of people
What is meant by indirect food production?
-when the microorganisms have an indirect effect- it is their actions on other food that is important
-e.g when you eat bread you are mainly eating flour, when you eat yoghurt or cheese it is mainly milk
What are the advantages of using microorganisms for these processes?
-no welfare issues- only need optimum conditions for growth
-an enormous range of microorganisms capable of carrying out many different chemical syntheses or degradations that can be used
-microorganisms have a very short life cycle and rapid growth rate. If given the right conditions of food, oxygen, and temperature, huge quantities of microorganisms can be produced in short space of time
-nutrient requirements of microorganisms are often very simple and relatively cheap
-genetic engineering allows us to artificially manipulate microorganisms to carry out synthesis reactions they would not do naturally
-conditions needed for growth include relatively low temperature, supply of oxygen and food, and removal of waste gases. Makes bioprocesses relatively cheap
What are the disadvantages of using microorganisms in indirect production?
-if the conditions aren’t ideal the microorganisms do not grow properly and so they don’t work efficiently
-conditions that are ideal for the microorganisms can also be ideal for microorganisms that cause food to go off or cause disease and so the processes have to be sterile (risk of contamination)
-increasingly the microorganisms used in food production have been genetically engineered and some people have ethical issues with the use of GM organisms- less publicly accepted
What is meant by direct food production?
-when microorganisms are used directly to produce protein you can eat- this is known as single cell protein (SCP)
- in recent years scientists are developing more ways of using microorganisms directly for fear of facing potential protein shortages
Give an example of a single cell protein and explain how it is made
-Quorn
-made of fungus Fusarium venetatum, a single cellar fungus that is grown in large fermenters using glucose syrup as a food source. The microorganisms are combined with egg white and then compressed and formed into meat substitutes
-it is suitable for vegetarians and is a healthy choice in general due to high protein and low fat
Give another example of the use of single-celled proteins
-used to feed animals we prefer to eat from fish to cattle
What are some of the advantages of using microorganisms to produce human food?
-microorganisms reproduce fast and produce protein faster than animals and plants
-they have a high protein content with little fat
-can use a wide variety of waste materials including human and animal waste, reducing costs
-can be genetically modified to produce the protein required
-production of microorganisms not weather dependent, it takes place constantly and can be increased or decreased to match demand
-no welfare issues when growing microorganisms
-can be made to taste like anything
What are some of the disadvantages of using microorganisms to produce human food?
-some microorganisms can also produce toxins if the conditions are not maintained at optimum
-microorganisms have to be separated from the nutrient broth and processed to make the food
-need sterile conditions that are carefully controlled adding to costs
-often involve GM organisms and many people have concerns about eating GM food
-the proteins has to be purified to ensure it contains no toxin or contaminants
-many people dislike the thought of eating microorganisms grown on waste
-has little natural flavour so needs additives
What is a bacterial culture?
-a population of one type of microorganism that been grown under controlled conditions
Why are cultures grown in fermentation vessels?
-to either obtain lots of the microorganism (e.g for production of single celled protein) or to collect lots of useful product that the microorganisms makes
What is the first method of culturing microorganisms, batch fermentation?
-where microorganisms are grown in individual batches in a fermentation vessel- when one culture ends it’s removed and then a different batch of microorganisms is grown in the vessel. This is known as closed culture
What is the second method of culturing microorganisms, continuous fermentation?
-this is where microorganisms are continually grown in a fermentation vessel without stopping. Nutrients are put in and waste products are taken out at a constant rate
Explain how each of the 5 conditions conditions inside the fermentation vessel is kept at the optimum for growth, and how this maximises the yield of microorganisms
1) pH = constantly monitored by a pH probe and kept at the optimum level = allows enzymes to work efficiently so high rate of reaction
2) temperature = kept constant by a water jacket that surrounds vessel = allows enzymes to work efficiently so high rate of reaction
3) access to nutrients = paddles constantly circulate fresh nutrient medium around the vessel = ensures that the microorganisms always have access to their required nutrients
4) volume of oxygen = sterile air is pumped into the vessel = makes sure that microorganisms always have oxygen for respiration
5) vessel kept sterile = superheated steam sterilises the vessel after each use = kills any unwanted organisms that may compete with one’s being cultured
What is a closed culture?
-when growth takes place in a vessel that’s isolated from the external environment- extra nutrients aren’t added and waste products aren’t removed from the vessel during growth
